<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <p>row</p>
    <div class="row">
        <div class="item"></div>
        <div class="item"></div>
        <div class="item"></div>
    </div>

    <p>column</p>
    <div class="column">
        <div class="item"></div>
        <div class="item"></div>
        <div class="item"></div>
    </div>
</body>
<style>
.row{
    display:flex;
    flex-direction: row;
}
.column{
    display:flex;
    flex-direction: column;
}
.item{
    background: red;
    height: 100px;
    width: 100px;
    border:1px solid #000;
}
</style>
</html>